Cameras have become very common thanks to the rapid development of camera technology, especially with the advances of digital imaging. In present era, people perceive term camera rather as a small digital device than as a larger unit with a film being exposed and later processed to photographs.
Whereas digital image sensors have succeeded film as the prevailing technique for recording an image, the image is still formed using objectives that closely correspond to those developed over past decades. The digital image sensors are typically much smaller than the normal film surfaces that were exposed and likewise the optics are also smaller in digital cameras. Still, most of the present cameras are supplied with fixed optics that is not changeable by the user, while more advanced photographers can chose a model with replaceable optics.
There are also add-on accessories that enable the user to change the optics e.g. by revolving a rotating disc with two or more different objectives.